共查询到20条相似文献,搜索用时 62 毫秒
1.
Jahan-Bakhsh Raoof Reza Ojani Mahsa Majidian Fereshteh Chekin 《Russian Journal of Electrochemistry》2010,46(12):1395-1401
The electrooxidation of D-penicillamine (D-PA) has been studied in the presence of potassium iodide in various buffered aqueous solutions (4.00 ≤ pH ≤ 9.00) at the
surface of glassy carbon electrode using cyclic voltammetry, differential pulse voltammetry and chronoamperometry. It has
been found that under optimum pH (pH 5.00) in cyclic voltammetry, the electrooxidation of D-PA in the presence of potassium iodide as a homogeneous mediator occurred at a potential about 220 mV less positive than
that in absence of potassium iodide at the surface of glassy carbon electrode. The homogeneous electrocatalytic oxidation
current wave of D-penicillamine was linearly dependent on the D-PA concentration and a linear calibration curve was obtained in the ranges 3.0 × 10−5−1.5 × 10−3 M and 9.0 × 10−6−1.2 × 10−4 M of D-PA with cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods, respectively. The detection limits (2σ)
were determined as 3.0 × 10−5 and 3.5 × 10−6 M with CV and DPV, respectively. This method was also used for voltammetric determination of D-PA in pharmaceutical preparation by standard addition method. 相似文献
2.
Wang-Zhuan Liu Xiao-Gang Wang Qing-Sheng Wu Ya-Ping Ding 《Journal of Analytical Chemistry》2009,64(1):54-58
A fast and convenient analytical technique has been suggested to detect dihydroxybenzene (DHB) isomers directly and simultaneously.
In 0.1 M HAc-NaAc buffer solution (pH 5.6), the reduction peaks of p -DHB and o -DHB were partly separated by differential pulse voltammetry at the glassy carbon electrode. By adding a surfactant (cetyl
pyridinium chloride) to enhance the detection sensitivity and using a semi-derivative technique to improve the separation,
p-DHB and o-DHB were detected simultaneously. The linear calibration ranges were 1.2 × 10−6 to 1.0 × 10−4 M for p -DHB and 8.2 × 10−7 to 1.0 × 10−4 M for o -DHB, with detection limits of 3.6 × 10−7 and 2.4 × 10−7 M, respectively. The proposed method has been applied to the direct determination of DHB isomers in water sample, and the
results were excellent.
The text was submitted by the authors in English. 相似文献
3.
The main purpose of this study is to develop an inexpensive, simple, selective and especially sensitive modified carbon paste
electrode (MCPE) for the determination of dopamine (DA) in pharmaceutical and human serum samples. The carbon paste electrode (CPE) has been modified by using [N,N′-bis(2-pyridine carboxamido)-1,2-benzene] nickel(II) complex (Ni(II)bpb) and the electrochemical
behavior of the modified electrode has been studied by cyclic voltammetry. The modified electrode shows an excellent electrocatalytic
effect on the oxidation of DA. Under optimum conditions, calibration plots are found to be linear in the range of 7.0 × 10−7−1.0 × 10−5 M (r
2 = 0.9940) and 1.0 × 10−5−1.0 × 10−4 M (r2 = 0.9945); the detection limit is 6.2 × 10−8 M. The preparation of MCPE is very easy. The electrode can be renewed by simple polishing. The proposed method shows good
sensitivity, reproducibility (RSD ∼ 2.9%), high stability (more than two month) without any considerable change in response
and recovery for the determination of DA. The prepared electrode has been successfully applied to the voltammetric determination
of DA in pharmaceutical and biological samples.
The article is published in the original. 相似文献
4.
Chunhai Yang Shenghui Zhang Yingxuan Liu Wensheng Huang 《Frontiers of Chemistry in China》2008,3(3):353-358
A multi-wall carbon nanotubes (MWNTs)-Nafion film-coated glassy carbon electrode (GCE) was fabricated and the electrochemical
behavior of ofloxacin on the MWNTs-Nafion film-coated GCE were investigated by cyclic voltammetry (CV), linear sweep voltammetry
(LSV) and electrochemical impedance spectroscopy (EIS). The oxidation peak current of ofloxacin increased significantly on
the MWNTs-Nafion film modified GCE compared with that using a bare GCE. This nano-structured film electrode exhibited excellent
enhancement effects on the electrochemical oxidation of ofloxacin. A well-defined oxidation peak attributed to ofloxacin was
observed at 0.97 V and was applied to the determination of ofloxacin. The oxidation peak current was proportional to ofloxacin concentration
in the ranges 1.0 × 10−8 to 1.0 × 10−6 mol/L and 1.0 × 10−6 to 2.0 × 10−5 mol/L. A detection limit of 8.0 × 10−9 mol/L was obtained for 400 s accumulation at open circuit (S/N = 3). This method for the detection of ofloxacin in human
urine was satisfactory.
__________
Translated from Chinese Journal of Applied Chemistry, 2007, 24(5): 540–545 [译自: 应用化学] 相似文献
5.
Tsung-Hsuan Tsai Tse-Wei Chen Shen-Ming Chen Ramiah Sarawathi 《Russian Journal of Electrochemistry》2012,48(3):291-301
The NiHCF-PEDOT, CuHCF-PEDOT and MnHCF-PEDOT films were prepared on glassy carbon electrode (GCE) by multiple scan cyclic
voltammetry and characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron
microscope (SEM) techniques. The advantages of these films are demonstrated for selectivity detection of ascorbic acid using
cyclic voltammetry and amperometric method. Interestingly, the NiHCF-PEDOT and CuHCF-PEDOT modified electrodes exhibited a
wide linear response range (5 × 10−6−3 × 10−4 M, R
2 = 0.9973 and 1.8 × 10−3−1.8 × 10−2 M, R
2 = 0.9924). The electrochemical sensors facilitated the oxidation of AA but not responded to other electroactive biomolecules
such as dopamine, uric acid, H2O2, glucose. The difference is MnHCF-PEDOT/GCE that no response to AA. In addition, the NiHCF-PEDOT and CuHCF-PEDOT modified
electrodes exhibited a distinct advantage of simple preparation, specificity, stability and reproducibility. 相似文献
6.
Polymerization of (O-tolidine), as ring substituted derivative of benzidine was achieved electro-chemically in organic solution containing Bu4NBF4 (0.2 M) in dichloromethane as supporting electrolyte. The film was obtained by electropolymerization in solution containing
monomer in various ratio ((5 × 10−4)–(5 × 10−2) M). This polymer was characterized by cycling voltammetry, impedance measurement, UV-visible and FT-IR spectroscopy. 相似文献
7.
Sayed Medhi Ghoreishi Mohsen Behpour Mohammad Hassan Motaghedi Fard 《Journal of Solid State Electrochemistry》2012,16(1):179-189
In this work, we investigate the electrochemical activity of dopamine (DA) and uric acid (UA) using both a bare and a modified
carbon paste electrode as the working electrode, with a platinum wire as the counter electrode and a silver/silver chloride
(Ag/AgCl) as the reference electrode. The modified carbon paste electrode consists of multi-walled carbon nanotubes (>95%)
treated with α-cyclodextrine, resulting in an electrode that exhibits a significant catalytic effect toward the electro-chemical
oxidation of DA in a 0.2-M Britton–Robinson buffer solution (pH 5.0). The peak current increases linearly with the DA concentration
within the molar concentration ranges of 2.0 × 10−6 to 5.0 × 10−5 M and 5.0 × 10−5 to 1.9 × 10−4 M. The detection limit (signal to noise >3) for DA was found to be 1.34 × 10−7 M, respectively. In this work, voltammetric methods such as cyclic voltammetry, chronoamperometry, chronocuolometry, differential
pulse and square wave voltammetry, and linear sweep and hydrodynamic voltammetry were used. Cyclic voltammetry was used to
investigate the redox properties of the modified electrode at various scan rates. The diffusion coefficient (D, cm2 s−1 = 3.05 × 10−5) and the kinetic parameters such as the electron transfer coefficient (α = 0.51) and the rate constant (k, cm3 mol−1 s−1 = 1.8 × 103) for DA were determined using electrochemical approaches. By using differential pulse voltammetry for simultaneous measurements,
we obtained two peaks for DA and UA in the same solution, with the peak separation approximately 136 mV. The average recovery
was measured at 102.45% for DA injection. 相似文献
8.
Jun Yue Bai Liang Wang Hong Jing Wang Peng Fei Huang Yu Qing Zhao Sheng Di Fan 《Mikrochimica acta》2006,156(3-4):321-326
The electrochemical behavior of epinephrine (EP) at a mercaptoacetic acid (MAA) self-assembled monolayer modified gold electrode
was studied. The MAA/Au electrode is demonstrated to promote the electrochemical response of epinephrine by cyclic voltammetry.
The possible reaction mechanism is also discussed. The diffusion coefficient D of EP is 6.85 × 10−6 cm2 s−1. In 0.1 mol L−1 phosphate buffer (pH 7.20), a sensitive oxidation peak was observed at 0.177 V, and the peak current is proportional to the
concentration of EP in the range of 1.0 × 10−5–2.0 × 10−4 mol L−1 and 1.0 × 10−7–1.0 × 10−6 mol L−1. The detection limit is 5 × 10−8 mol L−1. The modified electrode is highly stable and can be applied to the determination of EP in practical injection samples. The
method is simple, quick, sensitive and accurate. 相似文献
9.
Xiaomei Cao Yanhong Xu Liqiang Luo Yaping Ding Ying Zhang 《Journal of Solid State Electrochemistry》2010,14(5):829-834
A glassy carbon electrode (GCE) modified with the film composed of chitosan incorporating cetylpyridine bromide is constructed
and used to determine uric acid (UA) and ascorbic acid (AA) by differential pulse voltammetry (DPV). This modified electrode
shows efficient electrocatalytic activity and fairly selective separation for oxidation of AA and UA in mixture solution.
UA is catalyzed by this modified electrode in phosphate buffer solution (pH 4.0) with a decrease of 80 mV, while AA is catalyzed
with a decrease of 200 mV in overpotential compared to GCE, and the peak separation of oxidation between AA and UA is 260
mV, which is large enough to allow the determination of one in presence of the other. Under the optimum conditions, the anodic
peak currents (I
pa) of DPV are proportional to the concentration of UA in the range of 2.0 × 10−6 to 6.0 × 10−4 M, with the detection limit of 5.0 × 10−7 M at a signal-to-noise ratio of 3 (S/N = 3) and to that of AA in the range of 4.0 × 10−6 to 1.0 × 10−3 M, with the detection limit of 8.0 × 10−7 M (S/N = 3). 相似文献
10.
Ai-Lin Liu Jia-Dong Wang Wei Chen Xing-Hua Xia Yuan-Zhong Chen Xin-Hua Lin 《Journal of Solid State Electrochemistry》2012,16(4):1343-1351
A simple, rapid, sensitive, and accurate method for simultaneous electrochemical determination of procaine and its metabolite
(p-aminobenzoic acid, PABA) for pharmaceutical quality control and pharmacokinetic research was developed using a graphite paste
electrode. The differential pulse voltammetric results revealed that procaine and p-aminobenzoic acid, respectively, showed well-defined anodic oxidation peaks on a carbon paste electrode with a current peak
separation of 155 mV at a scan rate of 100 mV s−1. This well separation of the current peaks for these two compounds in voltammetry enables us to simultaneously determine
them. Good linearity (r > 0.998) between oxidation peak current and concentration was obtained in the range of 5.0 × 10−7–5.0 × 10−5 M for procaine and 5.0 × 10−7–2.0 × 10−5 M for PABA in pH 4.50 acetate buffer solution. The detection limit for both analytes is 5 × 10−8 M (S/N = 3:1). The present voltammetric method has been successfully used to determine trace p-aminobenzoic acid in procaine hydrochloride injection and procaine in plasma with a linear relationship of current to its
concentration ranging from 1.0 × 10−6 to 5.0 × 10−5 M (correlation coefficient of 0.9981) with a low detection limit of 5.0 × 10−7 M (S/N = 3:1). This validated method is promising to the study of pharmacokinetics in Sprague–Dawley rat and rabbit plasma after
an intravenous administration of procaine hydrochloride injection. 相似文献
11.
V. V. Senuta S. N. Bendrysheva M. A. Proskurnin 《Journal of Analytical Chemistry》2009,64(11):1174-1184
Thermal lens spectrometry was used for the differential kinetic determination of aniline (over the concentration range of
8 × 10−4–3.2 × 10−3 M) and 4-nitroaniline (2 × 10−4–1.6 × 10−3 M) present in combination in a single sample based on the oxidation reaction with periodate ions in an acidic medium (this
determination is not possible with the spectrophotometric monitoring of the rate of reaction). The thermal lens procedure
(λe = 488.0 nm; 80 mW) was characterized by good performance characteristics in the determination of aniline (c
min = 3 × 10−4 M; c
d = 8 × 10−4 M) and 4-nitroaniline (c
min = 7 × 10−5 M; c
d = 2 × 10−4 M), simplicity, and rapidity. 相似文献
12.
《Fresenius' Journal of Analytical Chemistry》1992,344(1-2):34-38
Summary The anodic voltammetric behaviour of pentachlorophenol at a silica gel-modified carbon paste electrode in aqueous solution
is reported. Adsorption of the fungicide onto the electrode under open-circuit conditions is followed by application of either
differential or square wave voltammetry. The results obtained by differential pulse voltammetry at pH 2.9, with a modifier
concentration of 10% and accumulation times of 120 and 300 s, allowed the development of a method to determine pentachlorophenol
in the ranges of 1.0×10−6–1.0×10−5 and 1.0×10−7–1.0×10−6 mol l−1. The relative standard deviation is 2.6% for a concentration of 2.0×10−7 mol l−1, with a detection limit of 1.8×10−8 mol l−1 (5 ppb). The effect of other chlorophenols was studied. The results obtained by square wave voltammetry showed a behaviour
typical of an irreversible electron transfer. Amplitude, step height and frequency were optimised, taking into account the
resolution of the voltammetric response. No improvement in sensitivity was obtained with respect to DPV. Good results were
obtained by applying the proposed differential-pulse voltammetric method to the determination of pentachlorophenol in a commercial
fungicide. 相似文献
13.
Adsorption and reduction of lovastatin were investigated by cyclic and square-wave voltammetry on a hanging mercury drop electrode
in aqueous solutions over a wide pH range (4–9). The electroreduction of lovastatin proceeds via a surface EC mechanism in
the whole pH range investigated. Using adsorptive stripping voltammetry, the drug yielded a well-defined voltammetric response
in Britton-Robinson buffer, pH 6 at −1.49 V which can be used to determine trace amount of lovastatin. The linear concentration
range of application was 1.0 × 10−8–1.0 × 10−7 M by using an accumulation potential of −0.5 V and a 90 s pre-concentration time. The method has been successfully applied
for the determination of lovastatin in a spiked human serum sample. 相似文献
14.
Yi Peng Junhui Xu Jia Zhao Bailin Hu Shengshui Hu 《Russian Journal of Electrochemistry》2008,44(2):206-212
The electrochemical response of phenol at acetylene black (AB)-dihexadecyl hydrogen phosphate (DHP) composite modified glassy
carbon electrode in the presence of cetyltrimethylammonium bromide (CTAB) was investigated. In this system, a sensitive oxidation
peak at 0.62 V (SCE) was obtained. The electrode process and the influence of CTAB on the oxidation of phenol were explored
by chronocoulometry and linear sweep voltammetry (LSV). Experimental conditions for the determination of phenol were optimized.
In the range of 5.0 × 10−7 to 1.2 × 10−5 M, the phenol concentration was linear with the oxidation peak current and the detection limit was found to be 1.0 × 10−7 M for 3 min accumulation. The method was applied for the determination of phenol in lake water and the results were satisfactory.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 2, pp. 222–229.
The text was submitted by the authors in English. 相似文献
15.
Agnieszka Nosal-Wiercińska Gra?yna Dalmata 《Monatshefte für Chemie / Chemical Monthly》2009,8(1):1421-1424
Abstract
This article proposes a simple and fast method of In(III) determination in the presence of Cd(II) and Pb(II). The catalytic activity of N-methylthiourea was used in the In(III) electroreduction, which also had a slight effect on the electroreduction process of Cd(II) and Pb(II). By applying square wave voltammetry it was possible to determine 3 × 10−7 mol dm−3 In(III) in the presence of 5 × 10−5 mol dm−3 Cd(II) and 1 × 10−4 mol dm−3 Pb(II) in 5 mol dm−3 NaClO4 at pH 2. The calibration curve for In(III) was linear from 3 × 10−7 to 5 × 10−4 mol dm−3. The relative standard deviation for In(III) determination was about 3.0%. 相似文献16.
A sensitive complex absorptive wave of Ca-ARS was obtained by using differential pulse voltammetry when a mercury film glass
carbon electrode was immersed in 0.1 mol L−1 KOH and 4.5×10−4 mol L−1 ARS solution. The peak potential obtained was −1.17 V (vs Ag-AgCl). The peak current was proportional to the concentration
of calcium in the range of 5.0×10−8−4.2×10−5 mol L−1. The detection limit was 2.0×10−8 mol L−1. This method was applied successfully to determining traces of calcium in blood serum. The electrochemical behavior of the
system was also studied by cyclic voltammetry, and the experiment results showed that the electrode process was an irreversible
absorptive with two electrons participating.
Translated from Journal of Beijing Normal University (Natural Science Edition), 2005, 41(2) (in Chinese) 相似文献
17.
de la Escosura-Muñiz A González-García MB Costa-García A 《Analytical and bioanalytical chemistry》2006,384(3):742-750
A new electroactive label has been used to monitor immunoassays in the determination of human serum albumin (HSA) using glassy-carbon
electrodes as supports for the immunological reactions. The label was a gold(I) complex, sodium aurothiomalate, which was
bound to rabbit IgG anti-human serum albumin (anti-HSA-Au). The HSA was adsorbed on the electrode surface and the immunological
reaction with gold-labelled anti-HSA was then performed for one hour by non-competitive or competitive procedures. The gold(I)
bound to the anti-HSA was electrodeposited in 0.1 mol L−1 HCl at −1.00 V for 5 min then oxidised in 0.1 mol L−1 H2SO4 solution at +1.40 V for 1 min. Silver electrodeposition at −0.14 V for 1 min followed by anodic stripping voltammetry were
then performed in aqueous 1.0 mol L−1 NH3–2.0×10−4 mol L−1 AgNO3. For both non-competitive and competitive formats, calibration plots in the ranges 5.0×10−10 to 1.0×10−8 mol L−1 and 1.0×10−10 to 1.0×10−9 mol L−1 HSA, respectively, with estimated detection limits of 1.5×10−10 mol L−1 (10 ng mL−1) and 1.0×10−10 mol L−1 (7 ng mL−1), respectively, were obtained. Levels of HSA in two healthy volunteer urine samples were also evaluated, using both immunoassay
formats. 相似文献
18.
A novel procedure was developed for the determination of trace cerium on the basis of anodic adsorption voltammetry of the
Ce(III)–alizarin complexon (ALC) complex at a carbon paste electrode (CPE). The procedure is convenient to determine cerium
individually in the presence of other rare earths because there is a 100 mV difference between the peak potentials of Ce(III)–ALC
and other rare earth(III)–ALC complexes in a supporting electrolyte of 0.08 M HAc–NaAc and 0.012 M potassium biphthalate (pH
4.7) when performing linear-scanning from −0.2 to 0.8 V (vs. SCE) at 100 mV/s. The second-order derivative peak currents are directly proportional to the Ce(III) concentration over
a range of 6.0 × 10−9–3.0 × 10−7 M. The detection limit is as low as 2.0 × 10−9 M (S/N = 3) for a 120 s preconcentration. An RSD of 3.5% was obtained for 15 determinations of Ce(III) at a concentration of 4.0
× 10−8 M on the same CPE surface. The method was applied successfully to the determination of cerium in samples of rare earth nodular
graphite cast iron. 相似文献
19.
A novel hydrogen peroxide (H2O2) biosensor was developed by immobilizing hemoglobin on the gold colloid modified electrochemical pretreated glassy carbon
electrode (PGCE) via the bridging of an ethylenediamine monolayer. This biosensor was characterized by UV-vis reflection spectroscopy
(UV-vis), electrochemical impendence spectroscopy (EIS) and cyclic voltammetry (CV). The immobilized Hb exhibited excellent
electrocatalytic activity for hydrogen peroxide. The Michaelis–Menten constant (K
m) was 3.6 mM. The currents were proportional to the H2O2 concentration from 2.6 × 10−7 to 7.0 × 10−3 M, and the detection limit was as low as 1.0 × 10−7 M (S/N = 3). 相似文献
20.
A new simple and inexpensive optical chemical sensor for cadmium(II) ions is presented. The cadmium sensing system was prepared
by incorporating 2-amino-cyclopentene-1-dithiocarboxylic acid (ACDA) on a triacetylcellulose membrane. The absorption spectra of the optical sensor membrane in Cd(II) solution showed a maximum
peak at 430 nm. The proportionality in intensity of the membrane color on the optode to varying amounts of Cd(II) suggests
its potential applications for screening Cd(II) in aqueous samples by visual colorimetry. The sensor provided a wide concentration
range of 3.0 × 10−6–3.4 × 10−4 M of Cd(II) ions with a detection limit of 1.0 × 10−6 M (0.2 μg/mL). The relative standard deviations for eight replicate measurements of 8.0 × 10−6 and 5.0 × 10−5 M Cd(II) were 2.7 and 2.3%, respectively. The response time of the optode was 6 min. The influence of interfering ions on
the determination of 1.0 × 10−5 M Cd(II) was studied and the main interferences were removed by extraction method. The sensor was applied to the determination
of Cd(II) in water samples. 相似文献